22 DEPARTMENT BULLETIN" i49% XT. S. DEPT. OP AGRICULTUBE 
medium soft, as an average, and the refractive index of back fat was 
1.4603. 
To show these results in graphic form the group of hogs was 
divided and arranged in series according to gains made on the corn- 
tankage ration. Figure 8 illustrates the results. The curves for 
corn with nonsoftening supplements and soy beans with a medium 
ration of shelled corn were taken from Figure 14, Department Bul- 
letin 1407 (4). The curve representing the hardening on corn with 
tankage following the softening on the soy-beans-corn ration shows 
clearly the influence of the corn-tankage ration. There was an unin- 
terrupted increase in firmness beginning at the point at which the 
hardening ration was first fed. It appears, however, that the harden- 
ing progressed more rapidly until a weight of about 200 pounds was 
attained than afterwards. This apparent behavior has been observed 
in connection with other lines of feeding and it is now believed that, 
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Fig. 8. — Hardening on corn with tankage after softening on soy beans with a 
medium (from 2 to 2.5 per cent) ration of shelled corn. Initial weights of 
pigs, 85 to 114 pounds 
in general, it is normal for the rate of hardening to decrease in rela- 
tion to the gain as the hog takes on weight and finish. 
Point A represents a gain of 39 pounds on the hardening ration 
after a similar gain, which was the average for the 31 hogs, on the 
soy-beans-corn ration. Reference to the grade limits indicated on 
the left side of Figure 8 shows clearly that at point A the hogs were 
still quite soft. 
The facts brought out above in Table 7, in Figure 8, and in the 
discussion furnished the basis for the following conclusion which 
was released after the 1925 conference (7) : 
Soy beans grazed with, a supplementary ration of 2.5 per cent of shelled corn 
with or without minerals self-fed to pigs starting at weights ranging from 85 
to 115 pounds and making gains of approximately 20 to 60 pounds through a 
period of from six to eight weeks will not produce firm carcasses in the usual 
case even though a subsequent gain in weight has been made by the pigs on corn 
with tankage equal to that previously made on the soy bean — 2.5 per cent corn 
ration. 
